Remove Controller screen, global button shortcuts, touch-toggled splash

UX overhaul:
- Drop the Controller screen entirely (touch zones, swipe gestures, HID
  gesture engine, four icon arrays, hand icon)
- Two persistent screens (Usage, Bluetooth) cycled by the middle PWR
  button; splash becomes a touch-toggled welcome animation
- Left button (GPIO 0): hold to send Space (Claude Code voice-mode PTT)
- Right button (GPIO 18): press to send Shift+Tab (mode toggle)
- Middle button on splash cycles animations instead of screens
- Remove USB plug/unplug auto-switch (Controller was the unplug target)
- Hide battery indicator on splash when in LOW state — it's noisy over
  the pixel-art animations

Implementation:
- Delete firmware/src/hid.{cpp,h} and touch.{cpp,h}; their roles fold
  into main.cpp button handlers and LVGL CLICKED events respectively
- splash_get_root() exposes the splash container so ui.cpp can attach
  a click handler for the dismiss-on-tap behavior
- Tap detection uses LVGL's built-in LV_EVENT_CLICKED with event
  bubbling on the inner panels — debouncing is handled by LVGL
- On Bluetooth screen, only the Reset Bluetooth zone is clickable;
  taps elsewhere are no-ops (no conflict with splash toggle)

Docs:
- README: drop Controller from screens table, rewrite Physical buttons
  table, remove Gesture controls section
- CLAUDE.md: update file map, button assignments, drop gesture refs

CLAUDE.md

@@ -10,20 +10,19 @@ This file is for future Claude Code sessions to bootstrap quickly. Read this fir
 - Touch: **CST9220** via I2C (SDA=15, SCL=14, INT=11, addr=0x5A)
 - PMU: **AXP2101** on same I2C bus (addr=0x34) — battery, USB VBUS, PWR button IRQ
 - IMU: **QMI8658** on same I2C bus (addr=0x6B) — accelerometer for auto-rotation
-- Buttons: GPIO 0 (left/back), GPIO 18 (right/forward), AXP PKEY (middle/PWR)
+- Buttons: GPIO 0 (left → Space/voice-mode), GPIO 18 (right → Shift+Tab/mode-toggle), AXP PKEY (middle → cycle screens; on splash → cycle animations)
 
 ## Architecture
 
 ```
-main.cpp        — setup(), loop(), button polling, rotation flash, USB-state screen switching
+main.cpp        — setup(), loop(), button polling (left→Space, right→Shift+Tab, mid→cycle), rotation flash
 display_cfg.h   — pin defines, extern object decls
-ui.{h,cpp}      — 4-screen UI (splash, usage, controller, bluetooth), screen cycling
+ui.{h,cpp}      — 3-screen UI (splash, usage, bluetooth); splash is touch-toggled, usage↔bluetooth via mid button
 splash.{h,cpp}  — 20×20 pixel-art animation engine, 24× upscale to 480×480
 imu.{h,cpp}     — accelerometer-driven rotation tracker (returns 0..3)
 power.{h,cpp}   — AXP2101 wrapper (battery %, charging, VBUS, PWR button)
-touch.{h,cpp}   — gesture state machine (zone taps, swipes, holds) on controller screen
+touch.{h,cpp}   — minimal tap detector → ui_toggle_splash() (Usage/Splash) or ble_clear_bonds() (BT reset zone)
 ble.{h,cpp}     — NimBLE peripheral: custom data service + HID keyboard
-hid.{h,cpp}     — gesture → HID keycode mapping
 data.h          — UsageData struct
 icons.h         — icon arrays. Battery (5×) are RGB565A8 with alpha; rest are raw RGB565.
 logo.h          — 80×80 RGB565 logo
@@ -54,7 +53,7 @@ The boot screen is `SCREEN_SPLASH` and only advances on a physical button press,
 2. **OPI PSRAM** required: `board_build.arduino.memory_type = qio_opi` in platformio.ini. Without this, `MALLOC_CAP_SPIRAM` returns NULL and the screen is black.
 3. **pioarduino platform required.** GFX Library for Arduino needs Arduino Core 3.x (`esp32-hal-periman.h`), not the 2.x that standard `espressif32` ships. We pin `pioarduino/platform-espressif32` 55.03.38-1.
 4. **LVGL 9 font patching.** `lv_font_conv` outputs LVGL 8 format. Must remove `#if LVGL_VERSION_MAJOR >= 8` guards, drop `.cache` field, add `.release_glyph`, `.kerning`, `.static_bitmap`, `.fallback`, `.user_data`. Without patching, fonts render invisible.
-5. **Touch reading must be centralized.** CST9220's `getPoint()` does a full I2C transaction. Calling it from both LVGL `my_touch_cb` and `touch.cpp:get_touch()` consumed each other's data, causing key-spam and broken swipes. Now `touch_read()` is called once per loop in main.cpp; both LVGL and gesture engine read from `touch_pressed/touch_x/touch_y` shared state.
+5. **Touch reading must be centralized.** CST9220's `getPoint()` does a full I2C transaction. Calling it from multiple places consumed each other's data and broke input. `touch_read()` is called once per loop in main.cpp; both LVGL `my_touch_cb` and `touch.cpp` read from shared `touch_pressed/touch_x/touch_y` state.
 6. **CO5300 needs even-aligned flush regions.** `rounder_cb` enforces this.
 7. **Touch `setSwapXY(true)` and `setMirrorXY(true, false)`** are the empirically-correct values for default rotation 0. IMU rotation logic doesn't change touch mapping (it does CPU-side rotation of the rendered pixels, so LVGL still thinks the display is portrait at 0°).
 8. **LVGL RGB565A8 is planar.** `w*h` RGB565 pixels followed by `w*h` alpha bytes; `data_size = w*h*3`, `stride = w*2`. Use `init_icon_dsc_rgb565a8()` for icons that overlap non-uniform backgrounds (e.g. battery over splash). Lucide source PNGs are black-on-transparent — converter must tint to white or icons render invisible. See `tools/png_to_lvgl.js`.